Present techniques use a solid support which is usually a spherical polystyrene bead covered with a protein (e.g. a polypeptide coming from a vaccinated animal) which has anti-body type properties. Said support is disposed in a test tube type receptacle into which a quantity of first reagent is admitted and, after an incubation period, the bead must be washed with water to remove the excess reagent. Said washing is manual as is the removal of the liquid, the tube being turned upside down and, the open end of the tube having tabs which prevent the bead from falling out. The operation must then be repeated with the second reagent, and its excess is again removed by washing, after which the tube is conveyed to an analysis unit proper, e.g. for photocolorimetric analysis by injecting a coloured reagent.
Although the principle of the support bead which successively holds the anticipated quantity of reagent is very simple and effective, the technique used gives little satisfaction. Indeed, the washing operations carried out by hand are not very reliable because washes and temperature conditions differ on different occasions, and they are unsuitable for analyses using grouped tests with different dosages because of the numerous handling operations which are necessary and introduce an inevitable risk for error.
The present invention aims to provide more reliable apparatus of simple design suitable for simultaneous analyses using several dosages and a minimum of handling.